Ribbon progressing and reversing device



Feb. 10, 1953 l. G. 0. BROWN RIBBON PROGRESSING AND REVERSING DEVICE Filed Sept. 8, 1950 QQMW M By mmm Attorneys Patented Feb. 10, 1953 2,627,965 I C E RIBBON PRGGRESSING AND REVERSING DEVICE Ivan G. 0. Brown, Yate, England, assignor to The British Vacuum Cleaner and Engineering Cornpany Limited, Leatherhcad, England, a. British company Application September 8, 1950, Serial No. 183,875 In Great Britain May 4, 1949 This invention relates to apparatus for effecting the progression and the automatic reversal of an inked ribbon which is wound on to one spool as it is unwound from another spool. Such apparatus is necessary in various kinds of devices employing an inked ribbon for producing a printed record on a paper sheet or the like, it being necessary to eifect gradual progression of the ribbon from one spool to the other in order to ensure even Wear thereof, and subsequently to provide for the automatic reversal of the ribbon after it has been completely unwound from one spool.

The invention finds a particular but not exclusive application in the time recorder described and claimed in co-pending application for Letters Patent Ser. No. 177,301, filed August 2, 1950.

According to the invention a ribbon progressing and reversing mechanism is provided wherein a driving shaft, adapted to be moved axially in either direction into driving engagement with one or the other of two spindles each adapted to carry a ribbon spool and out of engagement with the other said spindle, has mounted thereon a two-faced cam engaging with a resilient member arranged for movement axially of said shaft by an actuating member adapted to be moved in either direction axially of said shaft by the abutment with said member of one or the other of two pivoted levers, each of said levers being movable by the engagement therewith of a stop member provided on said ribbon at or near each end thereof, and said actuating member, on movement thereof in one direction, effecting movement of said resilient member to an over-centre position with respect to said cam to produce movement of said shaft in the reverse direction.

Reference will now be made to the accompanying drawings which illustrate a preferred form of construction of a ribbon reversing mechanism according to the invention and in which:

Fig. 1 is a plan view thereof and Fig. 2 is a detail View of a spring and cam device for effecting engagement of gears to drive the ribbon spools in one direction or the other.

The invention is illustrated as applied to the time recorder described in our aforesaid co-pending application and like parts of the mechanism hereinafter described and of the aforesaid time recorder will, for the sake of simplicity in comparison, bear like reference numerals.

Mounted to rotate in either side plate I of the time recorder and spindles 15, 15A which carry respectively on the ends thereof extending from the inner sides of the side plates 1, clutch or driving members 73, 16A. The spindles 15, 15A rotate in bushes ll, TIA mounted in said side plates I and are axially perforate at their inner ends. within the axially perforate ends of the spindles '7 Claims. (Cl. 197-165) A shaft 18 is mounted at either end 75, A and is rotatable and axially movable therein. Secured to the shaft 18 near either end thereof are further driving members l9, (9A, which are so disposed that a small axial movement of the shaft 18 in one direction or the other will effect engagement of driving members 16, 79 and disengagement of driving members 76A, 19A or vice versa. The shaft 18 has also secured thereto a gear wheel 8%], which is adapted to be driven in either position of said shaft 18 by the driving mechanism of the recorder through 1 suitable gearing (not shown) to rotate said shaft 18.

Ribbon spools (not shown) are adapted to be secured on the outer end of each of the spindles '15, 15A. Said spindles have mounted thereon light springs 8|, tlA, one end of each of which bears respectively on the bushes ll, TIA secured in the respective side plates I, the other end of the springs bearing against abutments 82, 82A integral with the respective spindles 15, 15A.

The shaft '38 has secured thereon a sleeve 83 formed with a circumferential cam having sloping cam faces 84, 84A which taper towards the outer periphery of the cam. The aforesaid gear wheel 86 is also conveniently mounted on the said sleeve 83. Mounted on the sleeve 83 is an annular helical spring 85 of a size such that it can rotate freely on the said sleeve 83, whilst engaging with, say, the cam face 84. The said spring is housed in a bridge 86, one member 86A of which houses the annular spring 85, whilst the other member 863 of which is slidably mounted on the shaft .18. The bridge 86 has also secured thereto two further spindles 81, 81A the free ends of which are slidably mounted in openings formed in side plates I. The ends of the spindles 81, 81A extend from either side of the said side plates l and are capable of axial movement therein to the limits imposed by shoulders 87C, 81D formed at the end of each spindle respectively.

As described in our aforesaid co-pending application, the ribbon H passes from the ribbon spools around guide rollers 60 and then through slots 63 formed in the ends of ribbon reverse levers 62 which are mounted to pivot laterally from each of the ribbon side frames 53. The said ribbon reverse levers '62 are adapted to en'- gage the ends of the spindles 81, 81A. I

In the following description of the operation of the apparatus described above, it will be assumed that the ribbon has been almost completely wound on to one spool and almost completely unwound from the other spool, and that the mechanism is in the condition shown in Fig.'1

Near either end thereof the ribbon has secured therein eyelets 88, of a thickness such that they will not pass through the slots 63 formed in the ribbon reverse levers 62. The gears 16A,

3 "A are in mesh and the ribbon H is therefore winding on to the spool mounted on spindle 15A and unwinding from the spool on spindle 15.

When the eyelet 88 in ribbon H reaches the slot 83 in the right hand ribbon reverse lever 62 further movement of the ribbon therethrough is prevented and further progression of the ribbon causes ribbon reverse lever 62 to be pivoted inwardly, on the side frame 53, towards the right hand side plate 1. Such movement imparts axial movement to the spindle 81 the end of which the lever 62 abuts, and accordingly, the spindles ill, 81A and the bridge 86 secured to the latter move to the left, as viewed in Fig. 1. The spring 85 housed in the member 86A of the bridge 86 is thus caused to ride up the cam face 84A of cam 84, the spring 85 being tensioned during this movement. As soon as the spring 85 passes over the edge of largest diameter of the cam '84 the spring 85 rides down the face 84B thereof, being urged to the point thereon of smallest diameter by the contraction of the tensioned spring 85 as it seeks to regain its normal untensioned condition.

The spindles 87, 81A are so located with respect to the bridge 86 that the shoulders 81C, 81D abut the inner sides of the side plates l in one extreme position of axial movement of the spindles 81, 81A and bridge 86 when the spring 85 has just reached its overcentre position with respect to the cam 84. Thus, when the spring 25 rides down the cam face 843 to the lowest point thereof, as mentioned in the foregoing paragraph, the radial movement of the spring in resuming its normal position is translated into axial movement of the shaft 18, the latter moving to the right, as viewed in Fig. 1 and causing engagement of driving members l6, l9 and disengagement of driving members 16A, 19A. Rotation is now imparted to spindle l and the ribbon H will now be wound on to the spool mounted thereon, the ribbon now being reversed and moving from left to right, instead of from right to left as heretofore described.

The ribbon will continue to wind on to the spool on spindle until the eyelet 83 at the other end of the ribbon engages in the slot 63 in theleft hand ribbon reversing lever 62 when the sequence of operations described above will take place but in the reverse direction.

The springs 8|, 81A are provided for the purpose of imparting a light braking action on spindles 15, 15A respectively, in order that, when either of the driving members '16, WA is disengaged, vibration shall not cause rotation of either spindle in a direction to cause slackening of the ribbon being unwound from the spool mounted thereon.

I claim:

1. A ribbon progressing and reversing mechanism, comprising a pair of axially alined spindles to carry respectively a pair of spools for a ribbon having stop members thereon adjacent to its respective ends, a driving shaft extending axially between the spindles and movable axially in one or the other direction, pairs of driving members on said shaft and the respective spindles, either of the pairs of driving members being engageable and the other pair thereof being disengageable by axial movement of said shaft in one or the other direction, a cam mounted on said shaft and having reversely sloping faces, a spring acting on said cam, a pair of pivoted levers having slots therein for the passage of the ribbon therethrough and displaoeable by abutment therewith of the respective stop members on the ribbon, and an actuating member cooperative with said spring and movable in one or another direction by the respective pivoted levers to shift the spring from one to the other face of the cam and thereby cause the spring to act on the cam to move said shaft in a direction to disengage one pair of driving members and to engage the other pair thereof.

2. A ribbon progressing and reversing mechanism, comprising a pair of spindles each adapted to carry a spool for a ribbon having stop members thereon adjacent to its respective ends, a driving shaft movable axially in one or the other direction, pairs of driving members for connecting said shaft and the respective spindles, either pair of said driving members being engageable and the other pair thereof disengageable by movement of said shaft in one or the other direction, a cam mounted on said shaft and having reversely coned faces thereon, an annular contractible helical spring cooperative with said cam and movable axially thereof from one to the other of said cam faces, a pair of pivoted levers having slots therein for the passage of the ribbon and displaceable by abutment therewith of the respective stop members on the ribbon, and an actuating member cooperative with said spring and reciprocable longitudinally of said shaft by one or the other of said levers to shift said spring from one face to the other face of said cam and thereby cause said spring to contract and act on said cam to shift said shaft axially and thereby disengage one pair of driving members and engage the other pair thereof.

3. A ribbon progressing and reversing mechanism as defined in claim 2, wherein said ribbon spools are mounted in axial alinement, and said shaft is mounted between and in alinemment with said spindles.

4. A ribbon progressing and reversing mechanism as defined in claim 2, wherein said spindles are mounted in axial alinement and have hollow proximate ends, and said shaft has its ends mounted in the hollow ends of the spindles.

5. A ribbon progressing and reversing mechanism as defined in claim 2, wherein said actuating member comprises a bridge engageable with opposite sides of said spring, and a shaft secured to the bridge and mounted for limited axial movement parallel to said driving shaft. I

G. A ribbon progressing and reversing mechanism as definedin claim 2, including means cooperative with each of said spindles for preventing rotation thereof in a direction to slacken the ribbon while the driving members for said spindle are disengaged.

7. A ribbon progressing and reversing mechanism as defined in claim 2, wherein said spindles are mounted in bushings and have abutments fixed thereon, and including a coil spring encircling each spindle and bearing at is ends against the respective bushing and abutment.

IVAN G. 0. BROWN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,485,765 Crawley Mar. 4, 1924 1,876,969 Krell Sept. 13, 1932 1,945,893 Going Feb. 6, 1934 

